Deficiency of fat-soluble vitamins (A,D,E, and K) was evaluated in 15 patients with exocrine pancreatic insufficiency secondary to chronic alcoholic pancreatitis. Mild to moderate steatorrhea was present in all patients despite oral pancreatic enzyme therapy for 27 +/- 4 months (mean +/- SE). Deficiency of a single fat-soluble vitamin was seen in six patients and deficiency of two fat-soluble vitamins was seen in two patients. One patient was deficient in three fat-soluble vitamins. Deficiency of vitamins A and E was most frequent. Treatment with specific vitamin supplements resulted in correction of these vitamin deficiencies. These data suggest that deficiency of a single or multiple fat-soluble vitamins is frequent even in treated patients with pancreatic insufficiency.